I've got tied shirts that've been tied for weeks, even months. When I'm ready to dye them, assuming I still have any idea how I tied them LOL, I soak them in soda ash till I get to them (I aim for 30-minutes minimum), mix the dye while they soak, and then dye them.

The color saturation is pretty good as long as I make sure to get the dye into all the folds and as long as the garment is thoroughly wet. I do make sure to press air bubbles out of pre-tied garments when I soak them in the soda ash.

Your shirts should be just fine in the plastic bags until you are ready to dye them. The only thing I'd worry about is molding (that forgotton pile of wet laundry from my 20's is still haunting me!).If it is going to be days before you get to dye the shirts you might want to just let them sit out of the bags. They will be fine to dye even if they've dried out, you'll just want to be sure that you saturate the shirts well with the dyes as moisture is vital to the fixing process.anet